WASHINGTON  U.S. officials began piecing together a case linking Osama bin Laden to the worst terrorist attack in U.S. history, aided by an intercept of communications between his supporters and harrowing cell phone calls from victims aboard the jetliners before they crashed yesterday.

Authorities were focusing some of their efforts on possible bin Laden supporters in Florida based on the identification of a suspected hijacker on one of the manifests of the four jets that crashed, law enforcement officials said.

The FBI was preparing to search locations in Broward County in south Florida and the Daytona Beach area in central Florida, Florida Department of Law Enforcement spokesman Rick Morera said.

The locations had links to the suspected bin Laden supporter on the jet manifest, officials said.

U.S. intelligence intercepted communications between bin Laden supporters discussing the attacks on the World Trade Center in New York and the Pentagon, according to Utah Sen. Orrin Hatch, the top Republican on the Senate Judiciary Committee.

"They have an intercept of some information that included people associated with bin Laden who acknowledged a couple of targets were hit," Hatch said in an interview. He declined to be more specific.

Hatch also said law enforcement has data possibly linking one person on one of the four ill-fated flights to bin Laden's organization.

Meanwhile, every possible lead was pursued. Authorities in New York were examining a van based on a lead it may be connected to the attacks, officials said.

The Taliban, Afghanistan's ruling Islamic militia, said bin Laden lacks the resources for such a terrorist attack.

Federal law enforcement officials were studying manifests for passengers, crew or service personnel with possible links to bin Laden.

The government unleashed legions of intelligence and law enforcement experts to begin identifying those who planned and carried out the attacks.

"Thousands of FBI agents in field offices and international legal offices are cooperating in this investigation," Attorney General John Ashcroft said. He said numerous federal law enforcement agencies were aiding the effort.